class Test:
    def __init__(self,foo):
        self.__foo=foo

    def __bar(self):
        print(self.__foo)
        print('__bar')

def main():
    test = Test('hello')
    
    #test.__bar()
    test._Test__bar()
    print('__bar')
    #print(test.__foo)

if __name__== '__main__':
    main()